An IUD is a small T-shaped plastic and copper device that's put into your womb (uterus) by a doctor or nurse.

It releases copper to stop you getting pregnant, and protects against pregnancy for between 5 and 10 years. It's sometimes called a "coil" or "copper coil".

• When inserted correctly, IUDs are more than 99% effective.
• An IUD works as soon as it's put in and lasts for 5 to 10 years, depending on the type.
• It can be put in at any time during your menstrual cycle, as long as you're not pregnant.
• It can be taken out at any time by a specially trained doctor or nurse. It's then possible to get pregnant straight away.
• Your periods can be heavier, longer or more painful in the first 3 to 6 months after an IUD is put in. You might get spotting or bleeding between periods.
• There's a small risk of getting an infection after it's been fitted.
• There's a small risk that your body may push out the IUD or it may move. Your doctor or nurse will teach you how to check it's in place.
• It can be uncomfortable when the IUD is put in, but you can take painkillers after, if you need to.
• It may not be suitable if you have had previous pelvic infections.
• It does not protect against sexually transmitted infections (STIs), so you may need to use condoms as well.

The IUD is similar to the intrauterine system (IUS), but instead of releasing the hormone progestogen like the IUS, the IUD releases copper into the womb.

The copper alters the cervical mucus, which makes it more difficult for sperm to reach an egg and survive. It can also stop a fertilised egg from being able to implant itself.

If you're 40 or over when you have an IUD fitted, it can be left in until you reach the menopause or you no longer need contraception.

An IUD can be fitted at any time during your menstrual cycle, as long as you're not pregnant. You'll be protected against pregnancy straight away.

Before your IUD is fitted, a GP or nurse will check inside your vagina to check the position and size of your womb. You may be tested for any existing infections, such as STIs, and be given antibiotics.

The appointment takes about 20 to 30 minutes, and fitting the IUD should take no longer than 5 minutes:

• the vagina is held open, like it is during cervical screening (a smear test)
• the IUD is inserted through the cervix and into the womb

Having an IUD fitted can be uncomfortable, and some people might find it painful, but you can have a local anaesthetic to help. Discuss this with a GP or nurse beforehand.

Let the person fitting your IUD know if you feel any pain or discomfort while you are having it fitted. You can ask to stop at any time.

You can also take painkillers after having an IUD fitted if you need to.

You may get period-type cramps afterwards, but painkillers can ease the cramps. You may also bleed for a few days after having an IUD fitted.

Once your IUD has been fitted, you may be advised to get it checked by a GP after 3 to 6 weeks to make sure everything is fine. Tell the GP if you have any problems after this initial check or if you want the IUD removed.

See a GP if you or your partner are at risk of getting an STI, as this can lead to an infection in the pelvis.

You may have an infection if you:

• have pain or tenderness in your lower abdomen
• have a high temperature
• have abnormal or smelly discharge

An IUD has 2 thin threads that hang down a little way from your womb into the top of your vagina.

The GP or nurse that fits your IUD will teach you how to feel for these threads and check that it's still in place.

Check your IUD is in place a few times in the first month and then after each period, or at regular intervals.

It's very unlikely that your IUD will come out, but if you cannot feel the threads or think it's moved, you may not be protected against pregnancy.

See a GP or nurse straight away and use additional contraception, such as condoms, until your IUD has been checked.

If you have had sex recently, you may need to use emergency contraception.

Your partner should not be able to feel your IUD during sex. If they can, see a GP or nurse for a check-up.

Your IUD can be removed at any time by a trained doctor or nurse.

If you're not having another IUD put in and do not want to get pregnant, use additional contraception, such as condoms, for 7 days before you have it removed.

It's possible to get pregnant as soon as the IUD has been taken out.

Most people with a womb can use an IUD.

A GP or nurse will ask about your medical history to check if an IUD is suitable for you.

The IUD may not be suitable if you:

• think you might be pregnant
• have an untreated STI or a pelvic infection
• have problems with your womb or cervix
• have unexplained bleeding between periods or after sex

People who have had an ectopic pregnancy or who have an artificial heart valve must consult their GP or clinician before having an IUD fitted.

Using an IUD after giving birth

An IUD can usually be fitted 4 weeks after giving birth (vaginal or caesarean). You'll need to use alternative contraception from 3 weeks (21 days) after the birth until the IUD is put in.

In some cases, an IUD can be fitted within 48 hours of giving birth. It's safe to use an IUD when you're breastfeeding, and it will not affect your milk supply.

Using an IUD after a miscarriage or abortion

An IUD can be fitted by an experienced GP or nurse straight after an abortion or miscarriage. You'll be protected against pregnancy immediately.

Although an IUD is an effective method of contraception, there are some things to consider before having one fitted.

Advantages:

• It protects against pregnancy for 5 or 10 years, depending on the type.
• Once an IUD is fitted, it works straight away.
• Most people with a womb can use it.
• There are no hormonal side effects, such as acne, headaches or breast tenderness.
• It does not interrupt sex.
• It's safe to use an IUD if you're breastfeeding.
• It's possible to get pregnant as soon as the IUD is removed.
• It's not affected by other medicines.
• There's no evidence that an IUD will affect your weight or increase the risk of cervical cancer, womb (uterus) cancer or ovarian cancer.

Disadvantages:

• Your periods may become heavier, longer or more painful, though this may improve after a few months.
• It does not protect against STIs, so you may need to use condoms as well.
• If you get an infection when you have an IUD fitted, it could lead to a pelvic infection if not treated.
• Most people who stop using an IUD do so because of vaginal bleeding and pain, although these side effects are uncommon.

Pelvic infections

There's a very small chance of getting a pelvic infection in the first 20 days after the IUD has been inserted.

You may be advised to have a check for any existing infections before an IUD is fitted.

See a GP if you've had an IUD fitted and you:

• have pain or tenderness in your lower abdomen
• have a high temperature
• have abnormal or smelly discharge

Thrush

There's some limited evidence that if you have an IUD fitted, you may have a slightly higher chance of getting thrush that keeps coming back.

Speak to a GP if you have an IUD and keep getting thrush. You might want to think about trying a different type of contraception.

Rejection

There's a small chance that the IUD can be rejected (expelled) by the womb or it can move (displacement).

If this happens, it's usually soon after it's been fitted. You'll be taught how to check that your IUD is in place.

Damage to the womb

In rare cases, an IUD can make a hole in the womb when it's put in. This may be painful, although sometimes there may be no symptoms.

If the GP or nurse fitting your IUD is experienced, the risk is extremely low. But see a GP straight away if you're feeling pain or cannot feel the threads of your IUD, as you may need surgery to remove it.

Ectopic pregnancy

If the IUD fails and you become pregnant, there's also an increased risk of ectopic pregnancy.

You can get the IUD for free, even if you're under 16, from:

• contraception clinics
• sexual health or genitourinary medicine (GUM) clinics
• GP surgeries
• some young people's services

Find a sexual health clinic

Contraception services are free and confidential, including for people under the age of 16.

If you're under 16 and want contraception, the doctor, nurse or pharmacist will not tell your parents or carer as long as they believe you fully understand the information you're given and the decisions you're making.

Doctors and nurses work under strict guidelines when dealing with people under 16. They'll encourage you to consider telling your parents, but they will not make you.

The only time a professional might want to tell someone else is if they believe you're at risk of harm, such as abuse.

In these circumstances, the risk would need to be serious, and they'd usually discuss it with you first.